That's like saying that you choosing not to speak is identical to you preventing someone else from speaking. You actually think those things are equivalent?
Sorry, I have the derp it seems. I'm not sure how you got to that. If deleting posts or an account is akin to me not speaking.. I don't understand how that would prevent someone else from speaking? Do you mean any comments that other people may have made, in reply? (Not trying to be dense.. please do explain!!)
I'm trying to compare choosing to manually delete posts made to facebook (which fb retains for whatever reason), with doing the same thing but making facebook not retain the information (one interpretation of this "right to forget"). Aside from where people may have replied or commented on things, I'm not sure how that's affecting someone else. I should probably read some more comments, they might answer that.